The biosynthesis, maturation and structure of the oligosaccharide components of membrane glycoproteins of lipid-enveloped animal viruses will be investigated in order to more clearly understand: (1) the specificity of glycosylation; (2) the role(s) of the carbohydrate moieties; and (3) the specific utilization of host cell machinery in virus assembly and glycoprotein processing. The advantages of studying cells in culture that are infected with vesicular stomatitis virus (VSV) or Sindbis virus are three-fold: (1) the genetic information of these viruses is limited and specifies only one (VSV) or two (Sindbis) species of virion membrane glycoproteins; (2) these are the only glycoproteins synthesized in significant quantities after host protein synthesis has been shut off by viral infection; and (3) the host provides the enzymatic machinery for the synthesis of virus-encoded glycoproteins. Previous studies of some novel intracellular maturation and biosynthetic processes utilized by the VSV glycoprotein are being continued and extended to include studies of the membrane glycoproteins of Sindbis virus and uninfected animal cells in culture. In addition, the mechanisms of glycosylation and the "precursor" and "mature" oligosaccharide structures for viral and cellular membrane glycoproteins will be studied in various lectin-resistant cell lines that are apparently defective at one or more steps in the complete oligosaccharide biosynthesis and maturation pathway.